Lipofectamine and Related Cationic Lipids Strongly Improve Adenoviral Infection Efficiency of Primitive Human Hematopoietic Cells

Abstract

Adenoviral vectors have the potential to infect a large number of cell types including quiescent cells. Their use in hematopoietic cells is limited by the episomal form of their DNA, leading to transgene loss in the progeny cells. However, the use of this vector may be interesting for short-term in vitro modifications of primitive human hematopoietic cells. Therefore, we have investigated the ability of adenovirus to transduce cord blood CD34⁺ cells. Several promoters were tested using the lacZ reporter gene. The PGK and CMV promoters induced transgene expression in 18–25% of the cells, whereas the HTLV-I and especially the RSV promoter were almost inactive. To improve infection efficiency, adenovirus was complexed with cationic lipids. Lipofectamine, Cellfectin, and RPR120535b, but not Lipofectin, Lipofectace, or DOTAP, markedly improved transgene expression in CD34⁺ cells (from 19 to 35%). Lipofectamine strongly enhanced infection efficiency of the poorly infectable primitive CD34⁺CD38^low cells (from 11 to 28%) whereas the more mature CD34⁺CD38⁺ cells were only slightly affected (from 24 to 31%). Lipofectamine tripled the infection of CFU-GMs and LTC-ICs derived from the CD34⁺CD38^low cell fraction (from 4 to 12% and from 5 to 16%, respectively) and doubled that of BFU-Es (from 13 to 26%). We conclude that cationic lipids can markedly increase the efficiency of adenovirus-mediated gene transfer into primitive hematopoietic cells.

Overview summary

Adenoviral vectors are currently used to infect a large variety of cell types and are able to infect quiescent cells. Reports have shown that primitive hematopoietic cells can be transduced with adenovirus. We tested in the present study the adenovirus-mediated expression in CD34⁺ cells of β-galactosidase as a function of the promoter used, showing that the CMV and PGK promoters are the most active in this cell population. We show further that adenovirual infection efficiency of CD34⁺ cells can be strongly enhanced by cationic lipids. Lipofectamine, one of the most potent cationic lipids tested, had an especially large effect on the infection of the CD34⁺CD38^low population, known to be primitive and largely quiescent. Lipofectamine enhanced strongly the infection efficiency of CFU-GMs and LTC-ICs and to a somewhat lesser extent that of BFU-Es. Adenoviral vectors may thus be used in combination with cationic lipids to transiently modify primitive hematopoietic cells.